Papillomaviruses and interferon.

Papillomaviruses are infectious agents which cause benign tumours, or warts, of cutaneous, uterine cervical and laryngeal epithelia. These infections are very common, yet no uniformly effective therapy exists. Current treatments do not selectively inhibit viral processes but destroy the infected epithelial cells. Since interferons have antiviral effects in vivo and in vitro, it was hypothesized that they might be useful for treating papillomavirus-induced conditions. Interferons have now been demonstrated to be effective in several forms of papillomavirus infection. In vitro, chronic treatment of bovine papillomavirus-transformed cells led to the loss of the papillomavirus genomes and return of the cells to a normal morphology. In humans, interferons have been used for treating laryngeal papillomatosis, cutaneous and anogenital warts and epidermodysplasia verruciformis. Partial and total remissions have been achieved with both intralesional and systemic administration. Ongoing studies aim to identify which conditions are most responsive, the optimal dosage and regimen and the most effective class of interferon. The mechanisms by which these responses occur are unknown, but are thought to depend on interferon inducing specific cellular proteins.